Field of the Invention
The subject matter disclosed herein relates circuit card assemblies and, more specifically, to removing thermal energy from circuit card assemblies associated with or coupling to these assemblies.
Brief Description of the Related Art
Circuit card assemblies are used for various purposes in today's electronic systems. The circuit card assemblies may include microprocessors (or other integrated circuits), or passive components such as resistors, capacitors, or inductors to mention a few examples. These circuit card assemblies are often arranged in a chassis. As the circuit card assemblies are operated, heat is generated by the electrical components disposed on these cards. Even if the components are not damaged by the heat, the operation of the circuit card assemblies may become inefficient due to the heat. If this heat is not removed however, it may cause damage to the circuit card assemblies or other devices that are near the circuit card.
Circuit card assemblies are held in place to the chassis by various types of locking arrangements. One such locking arrangement are wedge locks attached to the edges of the circuit card assembly. The wedge lock retains the circuit card assembly in the chassis and is a standardized design that fits within a chassis. When viewed in cross section, current heat sink designs typically have two portions that are integrally formed together and connected by an integral neck. Heat is removed from the circuit card in to the heat sink passing through a first of these portions, through the neck, through the second portion and then exiting the arrangement.
Unfortunately, the neck area in these previous arrangements is small which increases the thermal resistance of the circuit card heat sink. Due to the dimensional constraints of the wedge lock and the circuit card assembly themselves and other factors, it is not uncommon for the neck to be less than 1 mm in dimension. This type of sizing reduces thermal transfer in the system such that the performance of the circuit card assembly is reduced or components are damaged.
Previous attempts to increase the size of the neck to increase and improve the thermal paths have involved re-arranging the standard layout of the wedge lock assembly. Unfortunately, this disturbs the layout of the wedge lock and makes it unacceptable for many applications.